1. Field of the Invention
The present invention relates to a light emitting device having an element in which a light emitting material is sandwiched between electrodes (hereinafter referred to as light emitting element), and to a method of manufacturing the same. More particularly, the present invention relates to a light emitting device using a light emitting material with which EL (electro luminescence) can be obtained (hereinafter referred to as EL material).
2. Description of the Related Art
In recent years, a light emitting device (hereinafter referred to as EL display device) using light emitting elements utilizing an EL phenomenon of a light emitting material (hereinafter referred to as EL element) has been advancing. The light emitting element of an EL display device itself can emit light. Accordingly, differently from a liquid crystal display, no back light is necessary. Further, since the viewing angle thereof is wide, the EL display devices are suitable for outdoor uses.
Light emitting materials that can be used for an EL element include inorganic materials and organic materials. In recent years, organic materials which can be driven with low driving voltage, have been attracting attention. However, when the organic material is used for the EL element, there is a problem in that deterioration thereof develops rapidly. Since the organic material is oxidized, the efficiency of recombination of carriers becomes extremely worse, and thus, the EL phenomenon can not be obtained.
For the purpose of preventing the deterioration of the organic material used for an EL element, various ideas have been attempted. Generally, a method is known in which an EL element is covered with a ceramic material or a metal material to seal up the EL element in a space to shut out the outside air. EL displays manufactured by Tohoku Pioneer Co., Ltd. employ this method. Tohoku Pioneer Co., Ltd. provides a drying agent in the space.
Further, as the other means, technology disclosed in Japanese Patent Application Laid-open Nos. Hei 9-35868 and 11-54285 are known.